Assembly of a ceramic head on a metal rod for a hip prosthesis
AssigneeCeramiques Techniques Desmarquest
InventorsMichel Auclair, Christian Prats
Life of this patent
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Abstract
An assembly of a ceramic head fixed to a rod, which assembly is a component of a hip prosthesis that has improved distribution of the stresses transferred from the rod to the ceramic head. The ceramic head includes a blind recess, generally in the shape of a truncated cone, into which the male end of the rod is nested, in which this nesting together is provided without play between the ceramic head and the end of the rod in only a portion of the depth of the recess, while in the remaining portion of the recess there is no contact between the ceramic head and the end of the rod.
Claims9
An assembly for use in combination with an acetabular cup for forming an internal prosthesis for a hip joint, said assembly comprising:
- a ceramic head having extending from its outer surface a blind-ended recess in the shape, at least at the blind end of said recess, of a truncated cone of predetermined, small apex angle and dimensions;
- and
- a peg formed at the end of a rod and inserted within said recess to a predetermined depth, said peg having at least a distal end formed in the shape of a truncated cone of apex angle corresponding to the apex angle of said recess, and dimensions such that said peg is nested in said recess in a deep contact zone located toward the center of said ceramic head, said deep contact zone being about 15% to 80% of the depth of insertion of the peg in the recess, a non-contact zone between the peg and the recess being located between said deep contact zone and the surface of said ceramic head;
- said assembly providing optimal distribution of stresses from the peg to the ceramic head.
Dependencies are inferred from the claim text.